1. Technical Field
The present invention relates to a radiographic imaging system, a radiographic imaging device, a control device, and a radiographic imaging control method.
2. Related Art
FPDs (Flat Panel Detectors), in which a radiation-sensitive layer is disposed on a TFT (Thin Film Transistor) active matrix substrate and that can convert radiation directly into digital data, have been put into practice in recent years. Portable radiographic imaging devices (hereinafter also called “electronic cassettes”), that generate image information expressing a radiographic image manifested by radiation irradiated by using an FPD or the like and that store the generated image information, have been put into practice in recent years.
Because the electronic cassette is portable, a patient can be captured a radiographic image as is while on a stretcher or bed, and the place to be imaged can be adjusted by changing the position of the electronic cassette. Therefore, even patients who cannot move can be dealt with flexibly.
At an FPD, even in a state in which X-rays are not being irradiated, charges are generated due to dark current or the like, and the charges are accumulated in the respective pixels. Therefore, during standby, the electronic cassette repeatedly carries out a resetting operation of reading-out and deleting the charges accumulated in the respective pixels of the FPD. When instruction information that requests capturing of a radiographic image is received from a control device for control (a so-called console), the electronic cassette transmits to the console instruction information instructing the start of imaging after the resetting operation of one frame has been completed. When the console receives this instruction information, the console causes X-rays to be irradiated from a radiation generating device onto the electronic cassette. After a predetermined time period after transmitting the instruction information, the electronic cassette carries out reading-out of the charges accumulated in the respective pixels of the FPD.
In cases in which the communication between the electronic cassette and the console is wireless communication, there are cases in which the state of the communication becomes unstable and the console receives the instruction information late or cannot receive the instruction information.
Thus, Japanese Patent Application Laid-Open (JP-A) No. 2008-132216 discloses a technique of transitioning from the resetting operation to a charge accumulating state in which charges are accumulated in the respective pixels, not only in cases in which the electronic cassette receives a control signal of the start of irradiation of the X-rays, but also in cases in which the electronic cassette senses the start of irradiation of X-rays from the radiation generating device.
However, in the technique of JP-A No. 2008-132216, even if the start of irradiation of X-rays is sensed during the resetting operation, it is not possible to immediately transition to the charge accumulating state, and the radiation that is irradiated up to the transition to the charge accumulating state is wasted. If the X-ray irradiation time period is lengthened by an amount corresponding thereto, the amount of radiation that the subject is exposed to increases, which is not preferable.